1. Need to have a server allowed to connect to their pop/smtp servers. This will be an email proxy server. I have a Debian that is always online and has also a fixed internet IP address.
2. Sending emails:
For this I have installed emailrelay and configured it to my needs. The only problem I faced was to set it to run at startup, since it doesn't come with a /etc/rc.d/ startup script.
3. Receiving emails:
This is done on POP3 in my case and I found perdition that does POP/IMAP with loads of other options.
4. The final setup is like this:
- thunderbird is configured to connect to smtp/pop3 servers using non-standard ports: smtp on 60,0001 and pop3 on 60,002.
- My own debian server has installed emailrelay that listens on 60,001 and connects on 25 to the official email server. It also has perdition that listens on 60,002 and connects on 110 on the official email server.
- In case you don't have a fixed IP, you can use dyndns or similar service and use the chosen domain name in thunderbird.
There are loads of config possibilities but that's the way to go if you need email proxy. Both emailrelay and perdition have quite ok docs and senisble defaults so it should be no problem to set it up in 1 hr or less.